How to control the number of VCPUs of the control-domain (dom-0)

 in Xen, dom-0 can use both 'xm vcpu-pin' and 'xm vcpu-set' as well as other guest domains. However, in Xenserver, the same analogy won't work.

1. xe vm-vcpu-hotplug new-vcpus=<n> uuid=<uuid of the control domain> yields

Error: No matching VMs found

Alternatively, you may want to find the menu list file in the boot directory and specificy the number of CPU and the size of memory for the boot option.

"dom0_max_vcpus=X"

In order to dedicate those VCPUs, dom0_vcpus_pin needs to be specified in the boot option.

matplotlib contourf blank area

I am drawing a contour plot with fixed range (0,100). However, my data contains only (0,1) and when I call
plt.contourf(X,Y,Z,np.linspace(0,100,101), interpolation='neither',extend='neither')
It generated blank areas.

Add the following line ahead of contourf function.
plt.imshow(Z,interpolation='nearest',extent=[0,100,ymin,ymax], vmin=0,vmax=100)